Defensive publication

ABSTRACT

THE PRESS LATITUDE OF LITHOGRAPHIC PLATES HAVING GELATIN PRINTING SURFACES IS WIDENED BY CONTACTING THE PRINTING SURFACE WITH AN ACIDIC STOP BATH CONTAINING 0.5 TO 10% BY WEIGHT OF POLYPROPYLENE GLYCOL HAVING AN AVERAGE MOLECULAR WEIGHT IN THE RANGE FROM ABOUT 200 TO ABOUT 2000. THE STOP BATH IS OTHERWISE CONVENTIONAL AND, PREFERABLY, DOES NOT CONTAIN BENZYL ALCOHOL, DIETHYLENE GLYCOL OR TRIETHYLENE GLYCOL.

EFENSlVE UBLICATION UNITED STATES PATENT OFFICE Published at the requestof the applicant or owner in accordance with the Notice of Dec. 16,1969, 869 0.G. 687. The abstracts of Defensive Publication applicationsare identified by distinctly numbered series and are arrangedchronologically. The heading of each abstract indicates the number ofpages of specification, including claims and sheets of drawingscontained in the application as originally filed. The files of theseapplications are available to the public for inspection and reproductionmay be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to themerits of alleged invention. The Patent Oflice makes no assertion as tothe novelty of the disclosed subject matter;

PUBLISHED MARCH 7, 1972 T896,019 LITHOGRAPHIC REPRODUCTIONS Ralph DonaldZaflrann and Gale Francis Nadeau, In, both of 1669 Lake Ave., Rochester,N.Y. 14650 Filed Feb. 5, 1971, Ser. No. 113,106 Int. Cl. G03f 7/02 US.Cl. 96-33 No Drawing. 13 Pages Specification The press latitude oflithographic plates having gelatin printing surfaces is widened bycontacting the printing surface with an acidic stop bath containing 0.5to 10% by weight of polypropylene glycol having an average molecularweight in the range from about 200 to about 2000. The stop bath isotherwise conventional and, preferably, does not contain benzyl alcohol,diethylene glycol or triethylene glycol.

